CHESS F1/A1/F2 beam time was used for high resolution, X-ray diffraction data collection of cocrystalline preparations of eukaryotic transcription factors complexed with DNA. Expression of nuclear genes encoding proteins in eukaryotes is controlled at the level of RNA polymerase II transcription by a complex multisubunit assembly of proteins that interact specifically with each other and with three distinct DNA targets within each gene's promoter or control region. Our ongoing crystallographic measurements are examining three representative examples of transcription factors interacting with each of the DNA targets found in a typical class II promoter. Recent progress includes structure determinations for sterol regulatory element binding protein (SREBP) 1a bound to its DNA target the sterol regulatory element (StRE), and SREBP 2 also bound to the StRE. CHESS F1/F2 beam time was used for high resolution, X-ray diffraction data collection of a cocrystalline preparation of a eukaryotic translation factor complexed with RNA. Expression of nuclear genes encoding proteins in eukaryotes is controlled at the level of ribosomal translation by a complex multisubunit assembly of proteins that interact specifically with each other and with two distinct RNA targets within each gene's mRNA. Our ongoing crystallographic measurements are examining the structure of the cap-binding protein (eIF4E) recognizing the 5 mRNA cap. Recent progress includes structure determinations of complexes of eIF4E bound to a dinucleotide mRNA (7-methylGpppG), and eIF4E bound to both 7-methyl-GDP and 4EBP1 (an inhibitor of translation).